1) Field of the Invention
The present invention relates to glucosyltransferase inhibitors and methods for preventing dental caries by using the same, and more specifically to glucosyltransferase inhibitors comprising as an active ingredient an extract from fermented tea leaves having glucosyltransferase inhibitory action, methods for preventing dental caries by using the same and anticarious beverages and foods containing the same.
2) Description of the Related Art
Although a variety of theories were proposed in the past as to a possible cause for dental caries, it is now recognized that dental caries is a type of bacterial infectious disease based on the chemicoparasitic theory proposed by Miller.
The mechanism of occurrence of dental caries on the basis of the above theory is as follows. Namely, an enzyme called "glucosyltransferase" which is produced by oral streptococci, notably by Streptococcus mutans produces a sticky, insoluble polysaccharide (glucan) by using as a substrate sugar in the mouth. Cells of Streptococcus mutans (hereinafter abbreviated as "S. mutans") adhere to the surfaces of teeth by the glucan so produced, so that they form granules (dental plaques). Various microorganisms led by S. mutans are symbiotically growing in the dental plaques. Organic acids are produced by the metabolic activities of these microorganisms. The pH on the surfaces of the teeth drops as a result of the action of these organic acids, resulting in decalcification of the enamel surfaces. Consequently, dental caries takes place and proceeds.
Further, the formation of dental plaques is also believed to cause peridental diseases and bad breath in addition to dental caries.
Based on the findings described above, various investigations have been conducted with a view toward developing, as preventive measures for dental caries, antibacterial agents for oral microorganisms, inhibitors for glucosyltransferase, and enzymes capable of decomposing polysaccharides which glucosyltransferase forms using sugar as a substrate. However, no anticarious method having satisfactory effects has yet been found.
Prevention of dental plaque formation by suppressing the activities of glucosyltransferase is considered likely to become an effective means for the prevention of occurrence of dental caries especially in view of the fact that dental plaque formed by oral streptococci led by S. mutans acts as a cause for dental caries. To date, however, no practically usable glucosyltransferase activity inhibition substance has yet been found.